Building over Sewer Pipes

[bars03]

Hi

I am looking at building a conservatory to the rear of my terraced house. This will involve building a full height wall to the neighbours side and a dwarf wall for the rest. I have the problem of Sewer pipes (foul and water) running under the proposed build sight (approx 4.5m under surface) and an inspection cover.

I was just wondering on a couple of things.

Would either or both building regulations and water authority approval be required when building the foundations over the sewer pipes?

When building the foundations. I understand in these situations that I would have to set the foundations from the invert of the sewer pipes. What gap is recommended between the pipes and concrete footings? I assume packing the gap with sand is ok before placing the lintel over the pipes.

In regards to the inspection cover has anyone had experience where they have been given permission to close off the hatch completely? I was just wondering how likely this would be. I would prefer that there isn't a hatch within the conservatory but if I can't close it off, I will just build it up as I would envisage moving the hacth would be an expensive job.

Cheers View media item 32348 View media item 32348

 

[Richard C]

I have the problem of Sewer pipes (foul and water) running under the proposed build sight (approx 4.5m under surface) and an inspection cover.

Just a little confused as you say “foul & water” pipes; but both pictures appear to be the same & show what looks like the foul drain, is there another drain run?

Would either or both building regulations and water authority approval be required when building the foundations over the sewer pipes?

Is this your own property? If it’s a private sewer on private property (you need to check) then it’s yours (& your neighbours) responsibility & your LWA won’t be interested, they will only be concerned about what you discharge into it. Conservatories are exempt from Building Regs. so your LABC wont be concerned either but you should certainly ensure what you do as far as the foul drain is concerned meets Building Regs.

When building the foundations. I understand in these situations that I would have to set the foundations from the invert of the sewer pipes. What gap is recommended between the pipes and concrete footings? I assume packing the gap with sand is ok before placing the lintel over the pipes.

You will find all you need to know in Part H of the Building Regs here:
http://www.planningportal.gov.uk/uploads/br/BR_PDF_ADH_2002.pdf

In regards to the inspection cover has anyone had experience where they have been given permission to close off the hatch completely? I was just wondering how likely this would be. I would prefer that there isn't a hatch within the conservatory but if I can't close it off, I will just build it up as I would envisage moving the hacth would be an expensive job.

I would advise to move the foul drain outside the cons base if you possibly can. Failing that, it makes sense to ensure there are no problems with the existing drain before covering it up & it would be prudent to replace the section running under the cons with a single length of new pipe, bedded & protected as per current BR’s. You really need to loose the inspection hatch; you can get air tight hatches that you can tile but ask yourself if you really want one inside your cons & I wouldn’t advise you just close it up without being sure you have suitable roding access elsewhere! From the photo, the chamber doesn’t seem to be at a junction so it should be feasible to do away with it & fit a new one outside the cons base but which side you put it will depend on distances to the adjacent hatches not exceeding the maximum; to keep within the maximum distance you may need to fit a hatch either side. The extra work is inconvenient but the additional cost needn’t be that much & a small price to pay for peace of mind especially if you later have to dig up the cons base to fix a problem . Not much work for a man with a mini digger (if you can get one in the back) who could dig out for the cons base, new trench & chamber(s) + around a ½ days ground works to fit the new inspection chamber(s) lay a new one piece pipe, & backfill it all; you might find a man with the digger who can do the lot in a day. Strictly speaking it should be re-inspected by LABC but if you do it as repairs to a damaged pipe.

My own 5 x 5m cons has a foul drain (not shared) running right under the center & I did it as above but did not have to install a new chamber. It’s been there for 6 years now & no problems.

 

[jeds]

First thing really is to check to see if this is a private drain or public sewer? Your sewer provider should be able to tell you (normally on the phone) from the address and postcode.

 

[noseall]

Surely that's a typo! 4.5m under the surface as in metres????

If that is the case i would say it renders the job not just difficult but nigh on impossible.

Is that another pipe we can see running through the inspection chamber?

 

[Richard C]

Surely that's a typo! 4.5m under the surface as in metres????
If that is the case i would say it renders the job not just difficult but nigh on impossible.

Must confess that didn’t register but I count 7 courses so got to be a typo; 450mm I reckon.

Is that another pipe we can see running through the inspection chamber?

Bit confused about the 2 pipes but I can’t see it

Need more input OP

 

[Fluffster]

Looks like 2 pipes to me. One with an access cap looks about 6". They could be seperate drains run in the same trench with the surface water protected being enclosed.

Pete

 

[noseall]

Bit confused about the 2 pipes but I can’t see it

Surely you can see t'uther pipe Rich?

As Fluff has said, it appears there is an access cap on top.

 

[Richard C]

Surely you can see t'uther pipe Rich? As Fluff has said, it appears there is an access cap on top.

Think I can make it out now & if that is a pipe, it looks to be rather larger than the open 110mm alongside. Not seen one like that before; which is which do you reckon, surface water under the hatch?

I fear it may change things somewhat.

 

[Fluffster]

It may be a storm drain.

Pete